[gordner]

A catastrophic decompression can be just as dramatic as hollywood portrays...There are several examples of decompression literally tearing a fuselage apart. Air out of a valve stem is one example of a leak from a few atmospheres, so is a balloon popping.
The Aloha airlines aircraft that landed as a convertible had a fuselage crack lead to a catastrophic decompression that ended up tearing a good portion of the top of the cabin off, after a flight attendant was thrown hard into the structure by the escaping air and caused the crack to extend to a massive failure.
Gun fire in a pressurized aircraft is most certainly not a good idea. And to the point mentioned of high altitude drops from military aircraft, they depressurize before breaching the cabin.